Stereotype plate casting machine



April 16, 1957 -w. HARRIS 2,788,553

STEREOTYPE PLATE CASTING MACHINE Filed May 3, 1956 5 Sheets-Sheet 1 \NvENToQ m 1% ZZF W BY WTToQNEys April 16, 1957 w. HARRIS 2,788,553

STEREOTYPE PLATE CASTING MACHINE Filed May 3, 1956 3 Sheets-Sheet 2 INVENTOR WAT TORNEYS April 16, 1957 w. HARRIS 2,788,553

STEREOTYPE PLATE CASTING MACHINE Filed May 5, 1956 I5 Sheets-$heet 5 ATTORNEY United States Patent STEREOTYPE PLATE CASTING MACHINE Walter Harris, Altrincham, England, assignor to Linotype and Machinery Limited, London, England, a British company Application May 3, 1956, Serial No. 582,520

Claims priority, application Great Britain May 24, 1955 3 Claims. (Cl. 22-2) This invention relates to stereotype plate casting machines.

It is concerned with that type of machine which incorporates a motor-driven pump for pumping molten metal from a melting pot into an arched casting chamber formed between two mould members capable of relative movement for opening and closing of the mould, starting of the motor being effected by a manual control device consisting of a shaft which on rotation by hand in one direction actuates a switch in the motor circuit to produce operation of the pump.

The object of the invention is to provide a safety device for preventing a second charge of metal being pumped from the pot into the closed mould during the machine cycle.

. According to the main feature of the present invention, in a machine of the above type, there is provided a stop device associated with the control shaft to prevent a second operation of the pump while the movable mould member is in a closed position, release of the stop device being effected by the movable mould member when it is moved from its closed position to open the mould at the end of the casting operation.

In the preferred arrangement, the control shaft consists of a driving shaft section and a driven shaft section with an interposed dog clutch, the driving shaft section having a handle and being capable of axial movement to engage the clutch when the shaft sections are in a neutral rotative position, and the driven shaft section being coupled to the motor switch, the stop device acting on the driving shaft section to prevent return rotation thereof after rotation to turn the driven shaft section so as to close the motor switch; and the stop device comprises a spring-loaded plunger carried by the movable mould element, and a cam element on the driving shaft section having a shoulder for engagement by the plunger to prevent return movement of the shaft section.

It is preferred also to provide spring means to return the driving shaft section to its neutral position after release of the stop device, and also means for limiting angular movement of the driving shaft section in both directions.

One embodiment of the invention is illustrated by way of example in the accompanying drawings, in which:

Figure 1 is a diagrammatic view in elevation of a portion of the stereotype machine including the pump and its motor drive;

Figure 2 is a plan view of the manual control for the pump motor, with certain other parts of the machine shown diagrammatically;

Figure 3 is a plan view on an enlarged scale of a portion of Figure 1 including the safety device;

Figure 4 is a section on the line 44 of Figure 3; and

Figure 5 is a section on the line 55 of Figure 3.

The invention is applied to a known type of machine for casting curved stereotype plates, in which molten metal in a melting pct 11 (Fig. 1) is forced by a pump plunger 12 from a cylinder 13 up a spout 14 into 2,788,553 Patented Apr. 16, 1957 an arched casting chamber for the curved plate. The casting chamber is shown at 15 in Figure 2. One face of the chamber is formed by the peripheral wall of a cylinder 16 mounted on a vertical shaft 17. The other face of the chamber is afforded by the concave side of a matrix 18 located within an arched Water-cooled casting box 19. The casting box is mounted for horizontal travelling movement along the path A--A from a closed casting position (full lines) to a fully-open; position (chain lines).

The pump plunger 12 is operated by an electric motor Ztl mounted on the machine frame. The motor drives a horizontal shaft 21 by means of an endless chain 22 and sprockets 23, 24. On the shaft 21 is a worm 25 which drives a worm wheel 26 carried by a shaft 27. An eccentric pin 28 on the worm wheel is coupled by a crank rod 29 to a pivot pin 34} on a vertical reciprocating rod 31 that operates the pump plunger 12. The running of the motor 20 thus produces reciprocation of the rod 31 and of the plunger 12.

As shown in Fig. 2, the operation of the pump is controlled by a shaft assembly consisting of two aligned horizontal shaft sections 33, 34. The shaft section 33 is fitted with a lever arm 35 connected by a link 36 to a switch 37 for the motor 20. A second arm 38 on the shaft section 33 is connected at 39 to the top of a vertical rod 40 (Fig. .1) fixed at its lower end to a valve 41 that controls the flow of molten metal between the pump cylinder 13 and the metal pot 11.

The two shaft sections 33, 34 are adapted to be connected for rotation as a unit by means of a dog clutch 42 (Figs. 2, 3). One element 43 of the clutchis in the form of a tube, which is fixed on the shaft section 33; it acts also as a bearing for the adjacent end of the shaft section 34. The clutch element 44 is formed with a radial projection 58 Whose end is shaped with a stepped cam 59 with a shoulder 64 at the step. The opposed faces of the clutch element 43, 44 are provided with single teeth 45, 46 respectively, each extending through and capable of being engaged when the two shaft sections are in the neutral or inoperative position shown.

The free end of the shaft section 34 is fitted with a hand-lever 47. Adjacent the lever is a shaft bearing 48 forming part of a bracket 49. The bracket is secured by a stud and nut 50 to a portion 51 of the machine frame. A coil spring 52 located on the shaft 34 between the bracket 49 and the hand-lever 47 acts resiliently to hold the shaft towards the right in Figures 1 and 2, so as to disengage the clutch elements 43, 44. A collar 53 fixed on the shaft 34 acts as a stop.

Angular movement of the shaft section 34 and handlever 47 is limited by a stop pin 54 (Fig. 5) which projects from the bracket 49 into a segmental recess 55 in the collar 53. A coil tension spring 56 is connected between a stud 57 on the collar and the bracket 49. it acts to return the shaft section to its neutral position.

On the top of the casting box 19 is fixed a bracket 60 formed with a guide 61 for a plunger 62 spring-loaded at 63 to engage the cam surface 59 of the projection 58 on the clutch element.

When a plate is to be cast, the casting box is in the position shown in full lines Fig. 2. The hand-lever 47 is pushed inwardly to engage the clutch elements 43, 44; and it is then turned in an anti-clockwise direction (looking from the right of Figure 2) against the pull of the spring 56 so as to turn the shaft section 33. As a result, the shaft section 33 in turning causes the switch 37 to close the circuit to the motor 20 for operation of the pump plunger 12. At the same time the arm 38 on the shaft section 33 raises the rod 40 so as to close the valve 41, and the plunger in rising pumps metal from the cylinder 13 up the spout 14 into the casting chamber 15. As

soon=as the machine cycle has thus been started, the hand lever 47- can be released, and the shaft section 34 then slides axially under the action of the spring 52 to its normal position, .so disengaging the clutch 42..

At the end of the upward pumping stroke of the plunge'rlZ, the valve 41 opens, and the shaft section 33 turns back to its normal inoperative position (Fig. 2). The shaft section 34, however, is locked" in its advanced rotary position, by reason of the plunger 62 being engaged behind the shoulder 64 of the cam 59 on the projection 58; The teeth 45, 46 of the clutch elements are thus out of phase, so that it is impossible to re-engage the clutch by pushingin the'lever 47. By means of this safety device it is thus impossible inadvertently to pump a second charge ofmetal into the casting chamber.

When the plate has been cast, the casting box 19 is moved to its open position (chain lines); it carries the plunger62'clear of the step 59 on the clutch element 44; and the clutch element 44 is then reset by the return spring 56 to its normal or neutral position for re-engagement of the clutch at the end of the casting cycle. There is provided means, in the usual way, for closing the switch circuit to the motor 20 immediately the casting box 19 starts to move away from the cylinder 17, in order to prevent the pump being operated until the casting box is again in its fully-closed position at the end of the machine cycle.

I claim:

1 In a stereotype plate casting machine a closable mould comprising a fixed part and a relatively. movable part, a latch member fixed to said movable part, a reciprocating electrically driven pump for delivering molten metal to said mould, manually operable control means including a driving shaft having'limited axial and rota- 4- tional movement from a rest position, resilient means opposing each. of said" movements, the shaft -carrying a handle, the driving part of a clutch and a radially projecting latch member for coacting with the first named latch member, a driven shaft mounted for rotational but not axial movement and carrying the' driven part of the clutch in addition to a radially projecting member operatively connected to a switch controlling the supply of' current to the pump, the arrangement being such thatwhenthe mould is closed axial movement of the handle causes the clutch members to engage and subsequent limited rotating movement of the shaft engages the latching members and so preventsthe shaft from returning'to its rest position When'thehandle isreleased and also I01ates;the second shaft to close the switch to commence the normal cycle of the machine whiehcventually opens the switch and moves the driven clutch member into a position in which its driving clutch member cannot be engaged by axial movement of the driving shaft until the latch holding the latter is released by the opening of the mould. 2. In a stereotype casting machine as claimed in claim 1 a dog clutch between the driving and driven shafts having two diametral engaging-faces. 3. In a stereotype castingmachine as claimed in claim 1 an elongated stepped configuration of the operative-end of the latch member on the driving shaft and a resilient engaging part o'fthe latch member on the movable part of the mould.

References Cited in the file of this patent UNITED STATES PATENTS 

